Editing High-speed rail (section)

===Technologies===
[[File:Viaduc de la Haute-Colme 01 09.jpg|thumb|High-speed line on a viaduct to avoid ramp and road-crossing, with a [[British Rail Class 373]] from [[Eurostar]] in old livery crossing it.]]

[[File:Steigung NIM.jpg|thumb|A German high-speed line, with [[ballastless track]]]]

[[Continuous welded rail]] is generally used to reduce track vibrations and misalignment. Almost all high-speed lines are electrically driven via [[overhead line]]s, have [[in-cab signalling]], and use advanced switches using very low entry and [[Switch frog|frog]] angles. HSR tracks may also be designed to reduce vibrations originating from high speed rail use.<ref>{{Cite web|url=https://www.ejrcf.or.jp/jrtr/jrtr15/pdf/f38_tec.pdf|title=F38 tec}}</ref>

====Road-rail parallel layout====
[[File:NIM Baustelle2001 Leidorf Koeschinger Forst.jpg|thumb|A German high-speed line being built along a highway]]

The road-rail parallel layout uses land beside highways for railway lines. Examples include Paris/Lyon and [[Köln–Frankfurt high-speed rail line|Köln–Frankfurt]] in which 15% and 70% of the track runs beside highways, respectively.<ref>{{cite web |url=http://www.jhcrawford.com/energy/interstaterail.html |title=Interstate Rail Proposal |publisher=J.H. Crawford |access-date=17 October 2011 |archive-url=https://web.archive.org/web/20111008204136/http://www.jhcrawford.com/energy/interstaterail.html |archive-date=8 October 2011 |url-status=dead }}</ref> There are [[synergies]] to be achieved from such a setup as noise mitigation measures for the road benefit the railway and vice versa and furthermore less land must be taken through [[expropriation]] as land may have already been acquired for the construction of the other infrastructure. In addition to that, habitats of local wildlife are disrupted only once (by the combined rail/road right of way) instead of at multiple points. However, downsides include the fact that roads usually allow steeper grades and sharper turns than high-speed rail lines and thus co-locating them may not always be suitable. Moreover, both roads and railways often make use of narrow river valleys or mountain passes which do not allow a lot of infrastructure to be sited next to each other.

====Track sharing====
In China, high-speed lines at speeds between {{convert|200|and|250|km/h|mph|0|abbr=on}} may carry freight or passengers, while lines operating at speeds over {{convert|300|km/h|abbr=on|round=5}} are used only by passenger CRH/CR trains.<ref>{{cite web|url=http://www.ft.com/cms/s/0/353fecc8-40e1-11df-94c2-00144feabdc0,dwp_uuid=9c33700c-4c86-11da-89df-0000779e2340.html |archive-url=https://ghostarchive.org/archive/20221210/http://www.ft.com/cms/s/0/353fecc8-40e1-11df-94c2-00144feabdc0,dwp_uuid=9c33700c-4c86-11da-89df-0000779e2340.html |archive-date=10 December 2022 |url-access=subscription |url-status=live|title=China on track to be world's biggest network|author=Jamil Anderlini|work=Financial Times|date=5 April 2010 |access-date=12 April 2010}}</ref>

In the United Kingdom, [[High Speed 1|HS1]] is also used by regional trains run by [[Southeastern (train operating company)|Southeastern]] at speeds of up to {{Convert|225|km/h|0|abbr=on}}, and occasionally freight trains that run to central Europe.

In Germany, some lines are shared with Inter-City and regional trains at day and freight trains at night.

In France, some lines are shared with regional trains that travel at {{Convert|200|km/h|0|abbr=on}}, for example [[TER Pays de la Loire|TER Nantes-Laval]].<ref>{{cite news | url=https://www.ouest-france.fr/pays-de-la-loire/200-km/h-dans-le-ter-inaugural-sur-la-ligne-grande-vitesse-video-5105752 | title=Nantes-Laval. Le TER file à 200&nbsp;km/H sur la ligne à grande vitesse [vidéo]| newspaper=Ouest-France.fr| date=2 July 2017}}</ref>

Mixing trains of vastly different speeds and/or stopping patterns on the same tracks drastically reduces capacity,<ref>{{Cite web |title=Filderdialog Auswirkungen Mischverkehr|url=https://vm.baden-wuerttemberg.de/fileadmin/redaktion/m-mvi/intern/Dateien/PDF/Stuttgart_21/Filderdialog_Auswirkungen_Mischverkehr_120629.pdf}}</ref><ref>{{cite web |url=https://diglib.tugraz.at/download.php?id=60cc41b7f0080&location=browse |title=Tugraz}}</ref><ref>{{Cite web |url=https://tu-dresden.de/bu/verkehr/ibv/gvb/ressourcen/dateien/Abschlussarbeiten/2017_DA_Hannes_Ortlieb.pdf |title=2017 DA Hannes Ortlieb}}</ref> so usually a temporal separation (e.g. freight trains use the high-speed line only at night when no or only a few passenger trains operate)<ref>{{Cite web |date=2023-07-20 |title=ICE-Neubaustrecke: Nachts wird es in Kommunen mitunter leiser |url=https://www.fr.de/rhein-main/ice-neubaustrecke-nachts-wird-es-in-kommunen-mitunter-leiser-92412016.html |access-date=2023-08-17 |website=www.fr.de |language=de}}</ref> is employed or the slower train has to wait at a station or [[passing siding]] for the faster train to overtake - even if the faster train is delayed, thus delaying the slower train, too.